Sample # Volume NaOH used, mL Final buret reading, mL Initial buret reading, mL 18.8 23.4 41.2 1 10.4 8.4 mL 14.9 8.5 mL 3 32.7 8.5 mL 0.125 M NaOH Calculations (Show all work) 1. a. Calculate the number of moles of sodium hydroxide used for each titration. b.Calculate the number of moles of hydrochloric acid present in each sample. c.Calculate the concentration of the hydrochloric acid in each sample. d.Calculate an average for the three samples.

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need help with calculations for my chemistry lab! (Classic Titration 1 Lab) 

first picture is the data table that was gathered during the lab in which will be used to do the calculations.

second picture explains the intro, purpose, and the procedure of the whole lab as a reference if the data table or the whole thing does not make sense. 

I'd really appreciate it if I could get help on the calculations. Thank you!

Sample # Final buret reading, mL | Initial buret reading, mL| Volume NaOH used, mL
10.4
8.4 mL
8.5 mL
8.5 mL
1
18.8
2
3
23.4
41.2
14.9
32.7
0.125 M NaOH
Calculations (Show all work)
1. a. Calculate the number of moles of sodium hydroxide used for each titration.
b.Calculate the number of moles of hydrochloric acid present in each sample.
c.Calculate the concentration of the hydrochloric acid in each sample.
d.Calculate an average for the three samples.
Transcribed Image Text:Sample # Final buret reading, mL | Initial buret reading, mL| Volume NaOH used, mL 10.4 8.4 mL 8.5 mL 8.5 mL 1 18.8 2 3 23.4 41.2 14.9 32.7 0.125 M NaOH Calculations (Show all work) 1. a. Calculate the number of moles of sodium hydroxide used for each titration. b.Calculate the number of moles of hydrochloric acid present in each sample. c.Calculate the concentration of the hydrochloric acid in each sample. d.Calculate an average for the three samples.
Introduction
One of the most common problems dealt with by
chemists is to determine how much of something is
present in a sample. If the sample contains acid or
base, the determination of amount is usually determined
by titration. Acid-base titrations can be used to
measure the concentration of an acid or base in solution
Procedure
1)
solution into a beaker; record the exact molarity in your
data table and label the beaker.
Measure out 75 mL standard sodium hydroxide
Clamp a clean 50 mL buret to a ring stand. Use
2)
a funnel to pour solution into buret; rinse the buret three
times with 5 mL standard sodium hydroxide; discard
the rinsate.
and to calculate the molar mass of an unknown acid or
base.
Titration is a method of volumetric analysis – the use of
volumetric measurements to analyze an unknown. In
acid base chemistry, titration is most often used to
analyze the amount of acid or base in a sample or
solution. Consider a solution containing an unknown
amount of hydrochloric acid. In a titration experiment,
a known volume of the hydrochloric acid solution
would be titrated by slowly adding a standard solution
of a strong base such as sodium hydroxide. The titrant,
(the base in this case) reacts with and consumes the
acid via a neutralization reaction. The exact volume of
Use a funnel and fill the buret to above the zero
3)
mark with sodium hydroxide solution. Open the
stopcock and tap the buret gently to allow air bubbles to
escape from the tip; this should require no more than
2-3 mL sodium hydroxide solution.
4)
data table. NOTE – volumes are read from the top
down in a buret; always read from the bottom of the
meniscus, and remember to include the appropriate
significant figures.
5)
Record the initial volume of the buret in your
base needed to react completely with the acid is
measured. This is called the equivalence point of the
titration – the point at which stoichiometric amounts of
acid and base have been combined.
Using a pipet, transfer 10.0 mL unknown
hydrochloric acid solution to a 125 mL Erlenmeyer
flask. Add approx. 20 mL distilled water with swirling;
add three drops phenolphthalein indicator with
swirling.
6)
tip of the buret is inside the mouth of the flask. Place a
piece of white paper under the flask to make it easier to
detect the color change of the indicator at the endpoint.
7)
of the sodium hydroxide solution to flow into the flask
while continuously swirling the flask. Observe the
color change that occurs.
8)
Knowing the exact concentration and volume of the
titrant gives the number of moles of sodium hydroxide.
The latter, in turn, is related by stoichiometry to the
number of moles of hydrochloric acid present in the
unknown.
Position the flask under the buret such that the
Indicators are usually added to acid-base titrations to
detect the equivalence, or end point. The end point is
the point at which the indicator changes color and
signals that the equivalence point has been reached.
For example, in the HCl/ NaOH titration described
above, the pH of the solution is acidic before the
equivalence point, and basic afterwards. A pH of
exactly 7 corresponds to the neutral products, water and
sodium chloride.
Open the stopcock to allow approximately 5 mL
Continue to add sodium hydroxide slowly, in
0.5 mL increments, while swirling the flask. Use a
wash bottle to rinse the sides of the flask.
The progress of a titration can be followed by
measuring the pH of the solution being analyzed as a
function of the volume of titrant added. A plot of the
resulting data is called a pH or titration curve. Titration
curves allow a precise determination of the end point
without using an indicator.
9)
for 30 or more seconds with swirling, the endpoint has
been reached. Close the stopcock and record the final
buret reading for Run 1 in your data table.
10)
flask with a few mL distilled water.
When the first faint pink appears, and remains
Pour the solution out of the flask and rinse the
Purpose
The purpose of this experiment is to become familiar
with the titration process, in order to determine the
concentration of an unknown hydrochloric acid
solution.
11)
Repeat steps 4-10 with a second 10.0 mL
sample of hydrochloric acid.
12)
Repeat steps 4-10 with a third 10.0 mL sample
of hydrochloric acid.
Transcribed Image Text:Introduction One of the most common problems dealt with by chemists is to determine how much of something is present in a sample. If the sample contains acid or base, the determination of amount is usually determined by titration. Acid-base titrations can be used to measure the concentration of an acid or base in solution Procedure 1) solution into a beaker; record the exact molarity in your data table and label the beaker. Measure out 75 mL standard sodium hydroxide Clamp a clean 50 mL buret to a ring stand. Use 2) a funnel to pour solution into buret; rinse the buret three times with 5 mL standard sodium hydroxide; discard the rinsate. and to calculate the molar mass of an unknown acid or base. Titration is a method of volumetric analysis – the use of volumetric measurements to analyze an unknown. In acid base chemistry, titration is most often used to analyze the amount of acid or base in a sample or solution. Consider a solution containing an unknown amount of hydrochloric acid. In a titration experiment, a known volume of the hydrochloric acid solution would be titrated by slowly adding a standard solution of a strong base such as sodium hydroxide. The titrant, (the base in this case) reacts with and consumes the acid via a neutralization reaction. The exact volume of Use a funnel and fill the buret to above the zero 3) mark with sodium hydroxide solution. Open the stopcock and tap the buret gently to allow air bubbles to escape from the tip; this should require no more than 2-3 mL sodium hydroxide solution. 4) data table. NOTE – volumes are read from the top down in a buret; always read from the bottom of the meniscus, and remember to include the appropriate significant figures. 5) Record the initial volume of the buret in your base needed to react completely with the acid is measured. This is called the equivalence point of the titration – the point at which stoichiometric amounts of acid and base have been combined. Using a pipet, transfer 10.0 mL unknown hydrochloric acid solution to a 125 mL Erlenmeyer flask. Add approx. 20 mL distilled water with swirling; add three drops phenolphthalein indicator with swirling. 6) tip of the buret is inside the mouth of the flask. Place a piece of white paper under the flask to make it easier to detect the color change of the indicator at the endpoint. 7) of the sodium hydroxide solution to flow into the flask while continuously swirling the flask. Observe the color change that occurs. 8) Knowing the exact concentration and volume of the titrant gives the number of moles of sodium hydroxide. The latter, in turn, is related by stoichiometry to the number of moles of hydrochloric acid present in the unknown. Position the flask under the buret such that the Indicators are usually added to acid-base titrations to detect the equivalence, or end point. The end point is the point at which the indicator changes color and signals that the equivalence point has been reached. For example, in the HCl/ NaOH titration described above, the pH of the solution is acidic before the equivalence point, and basic afterwards. A pH of exactly 7 corresponds to the neutral products, water and sodium chloride. Open the stopcock to allow approximately 5 mL Continue to add sodium hydroxide slowly, in 0.5 mL increments, while swirling the flask. Use a wash bottle to rinse the sides of the flask. The progress of a titration can be followed by measuring the pH of the solution being analyzed as a function of the volume of titrant added. A plot of the resulting data is called a pH or titration curve. Titration curves allow a precise determination of the end point without using an indicator. 9) for 30 or more seconds with swirling, the endpoint has been reached. Close the stopcock and record the final buret reading for Run 1 in your data table. 10) flask with a few mL distilled water. When the first faint pink appears, and remains Pour the solution out of the flask and rinse the Purpose The purpose of this experiment is to become familiar with the titration process, in order to determine the concentration of an unknown hydrochloric acid solution. 11) Repeat steps 4-10 with a second 10.0 mL sample of hydrochloric acid. 12) Repeat steps 4-10 with a third 10.0 mL sample of hydrochloric acid.
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